Compressor

ABSTRACT

A compressor includes a compression chamber, a discharge chamber, a discharge port forming member and a discharge valve The compression chamber is formed in a cylinder block and in the compression chamber a refrigerant is compressed. The discharge chamber is formed in a cylinder housing which is fixed to the cylinder block. The refrigerant in the compression chamber is flowed into the discharge chamber. The discharge port interconnects the compression chamber and the discharge chamber. The discharge valve opens and closes the discharge port, and has a valve member and an arm member. The valve member faces to the discharge port for opening and closing the discharge port. The arm member urges the valve member toward the discharge port. The arm member and the valve member are integrally joined with each other.

BACKGROUND OF THE INVENTION

The present invention relates to a compressor and, in particular, to structure of discharge valves in a reciprocating compressor and a rotary compressor.

In a reciprocating compressor and a rotary compressor including a compression chamber which is formed in a cylinder block and in which a refrigerant is compressed, a cylinder housing which is fixed to one end of the cylinder block and in which a discharge chamber into which the refrigerant in the compression chamber flows is formed, a discharge port forming member in which a discharge port interconnecting the compression chamber and the discharge chamber is formed, such as valve plate, a discharge valve interposed between the cylinder housing and the valve plate for opening and closing the discharge port, in a discharge-valve method in which a reed valve type of discharge valve generally made of steel plate is used, a means for regulating a lift amount of the discharge valve by a retainer has been known in consideration of pulsation and durability due to vibration of the discharge valve. For example, please refer to Patent Document 1 and Patent Document 2.

It is noted that Patent Document 1 is Japanese Unexamined Patent Publication No 2000-130379 (please refer to pages 2, 3 of the specification and FIGS. 1 to 4 of the drawing). It is also noted that Patent Document 2 is Japanese Unexamined Patent Publication No. 2002-31058 (please refer to pages 2 to 4 of the specification and FIGS. 3, 4 of the drawing).

In the above-mentioned discharge-valve method, however, while the lift amount of the discharge valve is regulated by the retainer, resistance to discharge of a refrigerant gas to the contrary when the discharge valve is opened is increased. In addition, after the refrigerant gas is introduced from a suction chamber to the compression chamber and is compressed in the compression chamber to push the discharge valve away, and is discharged to the discharge chamber through the discharge port, and the discharge stroke ends, when the pressure differential between the compression chamber and the discharge chamber become substantially zero and the discharge valve closes the discharge port, high-pressure refrigerant gas is not sufficiently discharged and remains in a top-clearance region M that extends from a top dead center of a piston to the inside of the discharge port.

Since the remaining gas is high pressure, even if the volume of the top-clearance region M is relatively small, the remaining gas produces a large effect on the volume of suction refrigerant gas of low pressure, and therefore, compression efficiency of the compressor has not been enhanced. In addition, the increase of the resistance to discharge of the refrigerant gas when the discharge valve is opened also causes an increase of the over-compression in the compression chamber. As a result, the vibration in the compression chamber increases, and thereby causing vibration problem, noise problem and pulsation problem. In addition, due to the increase of compressive force, the load which is applied to parts inside the compressor is increased.

Although it is effective that the diameter of the discharge port is expanded to reduce the above-mentioned over-compression, since the discharge valve receives high-pressure discharge gas from the discharge chamber in a state that the discharge valve is closed in the suction stroke of the compressor, a part of the discharge valve which faces to the discharge port at least needs to sufficiently ensure its strength.

Therefore, since the expansion of the diameter of the discharge port increases compressive stress resulting from discharge pressure applied to the discharge valve, the thickness of the steel plate needs to be increased in order to ensure the strength of the discharge valve. However, as the thickness of the steel plate increase, the resistance to discharge upon opening the discharge port is further increased, thereby increasing the over-compression to the contrary. As a result, the reduction of the over-compression is not achieved. Besides, the expansion of the diameter of the discharge port increases the amount of high-pressure gas remaining in the top-clearance region M, thereby causing the reduction of the volumetric efficiency.

SUMMARY OF THE INVENTION

The present invention is directed to a discharge valve for use in a compressor, and the discharge valve includes a valve member and an arm member, which are integrally joined together, thereby casting various portions thereof in high-strength and lightweight materials that meets function and object of the various portions, and smoothly discharging a compressed refrigerant gas to a discharge chamber so as to reduce over-compression, and in addition, the discharge valve is capable of enhancing a compression efficiency of the compressor by reducing an amount of gas remaining in a top clearance region as much as possible.

The present invention provides the following features. A compressor includes a compression chamber, a discharge chamber, a discharge port forming member and a discharge valve. The compression chamber is formed in a cylinder block and in the compression chamber a refrigerant is compressed. The discharge chamber is formed in a cylinder housing which is fixed to the cylinder block. The refrigerant in the compression chamber is flowed into the discharge chamber The discharge port interconnects the compression chamber and the discharge chamber. The discharge valve opens and closes the discharge port, and has a valve member and an arm member. The valve member faces to the discharge port for opening and closing the discharge port. The arm member urges the valve member toward the discharge port The arm member and the valve member are integrally joined with each other.

Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments, together with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view illustrating a wobble plate type compressor according to a first preferred embodiment of the present invention;

FIG. 2 is a schematic sectional view illustrating a discharge valve and a related member according to the first preferred embodiment of the present invention;

FIG. 3A is a schematic plane view illustrating the discharge valve, which is partially cut away, according to the first preferred embodiment of the present invention;

FIG. 3B is a schematic perspective view illustrating the discharge valve, which is partially cut away, according to the first preferred embodiment of the present invention;

FIG. 4 is a schematic perspective view illustrating a discharge valve according to a second preferred embodiment of the present invention;

FIG. 5 is a schematic sectional view illustrating a discharge valve, a retainer and a related member according to a third preferred embodiment of the present invention;

FIG. 6A is a schematic rear view illustrating a valve member of a discharge valve according to a fourth preferred embodiment of the present invention; and

FIG. 6B is a schematic sectional view Illustrating the valve member of the discharge valve and a related member according to the fourth preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A compressor according to a first preferred embodiment of the present invention will now be described with reference to FIGS. 1, 2, 3A, 3B. In the compressor, a reed valve type of discharge valve is used.

The compressor shown in FIG. 1 is a wobble plate type compressor in a reciprocating compressor. Rotation of a drive shaft 1 oscillates a wobble plate 2 horizontally, thereby reciprocating a piston 3 in a cylinder bore 4 a formed in a cylinder block 4.

A rear cylinder housing 6 (hereinafter merely referred to a rear housing 6) is placed to one end surface of the cylinder block 4 through a discharge port forming member 5 such as a valve plate while a front cylinder housing 7 is placed to the other end surface of the cylinder block 4. On the inner circumferential side of the rear housing 6 a suction chamber 6 a and a discharge chamber 6 b are defined.

The valve plate 5 has formed therethrough a suction port 5 a and a discharge port 5 b in a place facing to the cylinder bore 4 a. The ports 5 a, 5 b interconnect the suction and discharge chambers 6 a, 6 b and a compression chamber 4 b which is defined between the piston 3 in the cylinder bore 4 a and the valve plate 5, respectively.

Referring to FIG. 2, a numeric designation 8 denotes a reed valve type of discharge valve, and includes a valve member 8 a and an arm member 8 b. The valve member 8 a is located on the side of the discharge chamber 6 b relative to the valve plate 5 so as to face to the discharge port 5 b, and opens and closes the discharge port 5 b in accordance with the pressure variation of the refrigerant gas compressed in the compression chamber 4 b. The arm member 8 b is such arranged that a basal end thereof together with a retainer 9 is fixed to the valve plate 5 by a pin 10, and has a predetermined rigidity, thereby urging the valve member 8 a in a direction closing the discharge port 5 b. An operational end of the arm member 8 b is integrally joined to the valve member 8 a by a means such as welding.

The valve member 8 a includes a board portion 81 a and a pillar-shaped protruding portion 81 b. The board portion 81 a has a larger diameter than the discharge port 5 b, and is capable of closely contacting the surface of the valve plate 5 functioning as a discharge port forming member in a predetermined area when the discharge valve 8 is in a closed state. The protruding portion 81 b extends from the board portion 81 a toward the discharge port 5 b so as to be inserted in the discharge port 5 b, and has a slightly smaller diameter than the discharge port 5 b. The board portion 81 a and the protruding portion 81 b are integrally formed so as to be solid by a forging or an injection molding.

Since a high pressure Pd1 of a discharge gas in the discharge chamber 6 b is applied to a part of the valve member 8 a which faces to the discharge port 5 b when the discharge valve 8 is in a closed state (or during a suction stroke), the thickness of the board portion 81 a of the valve member 8 a is formed at least so as to be relatively large in such an extent that the valve member 8 a has a strength for enduring the high pressure Pd1 of the discharge gas. Alternatively, the valve member 8 a uses a high-strength material.

The material of the valve member 8 a allows a metallic material. The valve member 8 a is, however, more preferably cast in a resin material by an injection molder to reduce its weight in such a manner that a pressure Pd2 of the refrigerant gas compressed in the compression chamber 4 b smoothly flows into the discharge chamber 6 b when the discharge valve 8 is in an opened state (or during a discharge stroke).

Even if the valve member 8 a is made of metallic material, the arm member 8 b needs to have an appropriate rigidity of spring so as to easily open and close the discharge port 5 b and have a predetermined durability and, therefore, the arm member 8 b is more preferably made of metallic material which is different from the metallic material of the valve member 8 a.

The discharge valve 8 of the first embodiment is operated as shown in FIG. 2.

First, when the piston 3 starts its suction stroke, the suction valve 11 opens and suction refrigerant gas is supplied from the suction chamber 6 a into the compression chamber 4 b in the cylinder bore 4 a. At the same time, the valve member 8 a of the discharge valve 8 closes the discharge port 5 b. At this point, the pressure Pd1 of the discharge gas in the discharge chamber 6 b is applied to the board portion 81 a of the valve member 8 a, and is received by a part where the board portion 81 a and the valve plate 5 contact in the area, thereby closing the discharge port 5 b in a state that the board portion 81 a and the valve plate 5 closely contact each other.

Although during the suction stroke of the piston 3, stress load which the pressure Pd1 of the discharge gas supplies to a part of the board portion 81 a of the valve member 8 a which faces to the discharge port 5 b, or a middle of the board portion 81 a of the valve member 8 a is increased, since the valve member 8 a has large thickness, or the valve member 8 a uses a high-strength member, the valve member 8 a does not tend to cause its plastic deformation, thereby maintaining the entire flat state. Accordingly, the board portion 81 a of the valve member 8 a closely contacts the surface of the valve plate 5 utilizing the pressure Pd1 of the discharge gas.

When the piston 3 starts a compression stroke after having reached a bottom dead center, the suction valve 11 closes the suction port 5 a to raise the pressure in the compression chamber 4 b. When the piston 3 approaches a top dead center, the pressure Pd2 of the compression gas in the compression chamber 4 b pushes the discharge valve 8 away to be opened, and the compression gas is flowed into the discharge chamber 6 b.

At this point, the arm member 8 b of the discharge valve 8 does not need to be thickened with the valve member 8 a, and therefore, the arm member 8 b tends to be easily bent by the pressure Pd2 of the compression gas. Thus, the compression gas is smoothly discharged to the discharge chamber 6 b without increasing resistance to the discharge.

When the piston 3 reaches the top dead center and a large part of the compression gas in the compression chamber 4 b is discharged to the discharge chamber 6 b, and pressure differential between the discharge chamber 6 b and the compression chamber 4 b becomes slight, the valve member 8 a closes the discharge port 5 b by urging force of the arm member 8 b. At this point, since the shape of the protruding portion 81 b of the valve member 8 a to be fitted into the discharge port 5 b is shaped so as to closely resemble that of the discharge port 5 b, and a gap between a circumferential wall of the protruding portion 81 b and a wall surface of the discharge port 5 b is narrowed, an amount of compression gas that remains in the gap becomes extremely small. That is, an amount of compression gas that remains in a top-clearance region M of the piston 3 becomes extremely small by reducing the volume of the top clearance region M of the piston 3. Therefore, deterioration of the volumetric efficiency due to the remaining compression gas upon starting the suction stroke is prevented.

The discharge valve of the compressor according to the present embodiment produces the following beneficial effects.

(1) A s well as the entire valve member 8 a of the discharge valve 8, only a part of the valve member 8 a which corresponds to the discharge port 5 b is thickly cast in an independently high-strength and lightweight material irrelevantly to the thickness of the arm member 8 b. Thus, even if the diameter of the discharge port 5 b is expanded in order to reduce flow resistance of the pressure Pd2 of the compression gas toward the discharge chamber 6 b and reduce an over-compression, sufficient strength and durability to the pressure Pd1 of the discharge gas which is applied to the valve member 8 a during the suction stroke are obtained.

(2) Since the expansion of the diameter of the discharge port 5 b is allowed, a flow of the compression gas of the pressure Pd2 to the discharge chamber 6 b upon the compression stroke is smoothly achieved. In addition, since the shape of the protruding portion 81 b of the valve member 8 a is shaped so as to closely resemble that of the discharge port 5 b, and a gap between the protruding portion 81 b and the discharge port 5 b is narrowed. Therefore, the amount of gas that remains in the top-clearance region M is reduced, and deterioration of the volumetric efficiency in compression chamber 4 b upon the suction stroke is prevented.

(3) Since the arm member 8 b and the valve member 8 a are two individual members and are joined with each other, the material and thickness of the arm member 8 b are individually selected irrelevantly to those of the valve member 8 a. Therefore, the arm member 8 b is capable of using a thin steel plate as a material, and the discharge valve 8 tends to be easily opened to the pressure of the compression gas upon the compression stroke. Thus, the discharge resistance of the discharge valve 8 is reduced and the over-compression is also reduced.

A compressor according to a second preferred embodiment of the present invention will now be described with reference to FIG. 4. In the present embodiment, the discharge valve 8 of the compressor according to the first embodiment is modified.

A discharge valve 83 of the present embodiment is modified in material and shape of the arm member 8 b of the discharge valve 8 of the above-mentioned compressor. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.

As shown in FIG. 4, the discharge valve 83 of the compressor of the present embodiment includes a valve member 83 a and an arm member 83 b similarly to that of the first embodiment. The valve member 83 a is such constructed that a board portion 831 and a pillar-shaped protruding portion 832 are integrally cast with each other similarly to that of the first embodiment.

The arm member 83 b has used a steel wire in place of the steel plate of the first embodiment. A basal end of the arm member 83 b is fixed to the valve plate 5 by a pin, and an operational end thereof is such constructed that the distal end of the operational end is fixed to the side face or top face of the board portion 831 by an inserting means or a welding means in an embedded state, thereby urging the board portion 831 of the valve member 83 a toward the side of the discharge port 5 b so as to closely contact the surface of the valve plate 5. Thus, the discharge valve 83 opens and closes the discharge port 5 b.

It is noted that the arm member 83 b formed by this steel wire may include a plurality of steel wires without limitation of the single steel wire, and that the arm member 83 is preferably made of metallic material provided with resilient force and rigidity.

When the arm member 83 b is constructed by an appropriate number of steel wires, the arm member 83 b is formed only by cutting the wires upon manufacturing the arm member 83 b, and therefore, the material is hardly wasted. The urging force of the arm member 83 b is freely modified by selecting the thickness and the number of the steel wires

A compressor according to a third preferred embodiment of the present invention will now be described with reference to FIG. 5. In the present embodiment, the retainer 9 adhered to the discharge valve 8 of the compressor according to the first embodiment is modified.

A retainer 91 of the present embodiment functions so as to regulate a lift amount of the discharge valve 8 of the above-mentioned compressor and a fitting position thereof is modified. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.

As shown in FIG. 5, the retainer 91 which functions to regulate the lift amount of the discharge valve 8 is a protruding member and is formed so as to extend from the inner wall surface of the discharge chamber 6 b of the rear housing 6 toward the valve member 8 a of the discharge valve 8. When the distal end of the protruding member contacts the discharge valve 8, a maximum lift amount of the discharge valve 8 is regulated.

Since the retainer 91 is integrally cast with the rear housing 6, a metallic retainer is not needed, thereby achieving reduction of the number of parts and time for assembly.

A compressor according to a fourth preferred embodiment of the present invention will now be described with reference to FIGS. 6A and 6B. In the present embodiment, the valve member 8 a of the discharge valve 8 of the compressor according to the first embodiment is modified.

A valve member 84 a of the present embodiment functions such that a board portion 841 of the valve member 84 a is easily distanced from the valve plate 5. Therefore, for convenience of explanation, the same numeric designations are used for parts in common with the first embodiment. An explanation of the configuration parts in common with the first embodiment is omitted, and the aforementioned explanation is incorporated.

Referring to FIG. 6B in combination with FIG. 6A, the board portion 841 of the valve member 84 a has formed an annular groove 843 concentric with the board portion 841, in the back surface of the board portion 841, that is, in a part of the surface of the board portion 841 which faces to the valve plate 5 and at least contacts the valve plate 5 in a predetermined area.

Since the board portion 841 has formed therein the annular groove 843, in the suction stroke the area of a portion of surface contact between the board portion 841 and the valve plate 5, which are stuck to each other by oil, is relatively small. In addition, when a discharge valve 84 opens the discharge port 5 b in the compression stroke, the board portion 841 is easily distanced from the discharge port forming member 5. Therefore, in the first motion of the discharge valve 84, resistance to valve opening is relatively small, thereby hardly causing resistance to discharge. Further, the annular groove 843 is formed at the time when the board portion 841 of the valve member 84 a is formed, and thereby simply forming the concentric annular groove 843.

The present invention is not limited to the above-mentioned first to fourth embodiments, but is variously modified within a range of the purpose of the invention. For example, the following alternative embodiments are also practiced.

In the first preferred embodiment, although two members of the valve member 8 a and the arm member 8 b are integrally joined with each other by a joining means such as welding, the two members may be integrally joined with each other, for example, by sandwiching an appropriate range of the outer peripheral surface of the board portion 81 a of the valve member 8 a with the distal ends of the arm member 8 b up and down, or by press-fitting the board portion 81 a of the valve member 8 a to the distal end of the arm member 8 b.

In the first preferred embodiment, although two members of the valve member 8 a and the arm member 8 b are formed by different materials such that the valve member 8 a is made of resin material and the arm member 8 b is made of metallic material, if the arm member 8 b is at least made of the material having rigidity of spring having urging force in a direction closing the discharge port 5 b, the two members may be made of the identical material.

In the valve member 8 a of the discharge valve 8 of the first preferred embodiment, although the board portion 81 a and the protruding portion 81 b are integrally formed so as to be solid by a forging or an injection molding, the board portion 81 a and the protruding portion 81 b may be are combined with each other by a means such as press-fitting or screwing after being separately cast.

In the first preferred embodiment, although the discharge valve of the wobble plate type compressor is illustrated, a discharge valve of a single headed piston type compressor may be adopted without limiting to the discharge valve of the wobble plate type compressor. For example, a discharge valve of a rotary compressor such as vane compressor or scroll type compressor may be adopted.

In the second preferred embodiment, the arm member 8 b of the discharge valve 8 is formed by a steel wire. The shape of the steel wire is not limited to a round bar, but may be a thin and rectangular steel plate.

In the third preferred embodiment, although the retainer 91 is integrally formed with the inner wall surface of the discharge chamber 6 b of the rear housing 6, the retainer 91 may be attached to the inner wall surface of the discharge chamber 6 b of the rear housing 6 by a screw so as to permit the attachment and remove.

Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein but may be modified. 

1. A compressor comprising: a compression chamber in which a refrigerant is compressed, formed in a cylinder block; a discharge chamber formed in a cylinder housing which is fixed to the cylinder block, the refrigerant in the compression chamber being flowed into the discharge chamber; a discharge port which interconnects the compression chamber and the discharge chamber; and a discharge valve for opening and closing the discharge port, the discharge valve comprising: a valve member facing to the discharge port for opening and closing the discharge port; and an arm member for urging the valve member toward the discharge port, wherein the arm member and the valve member are integrally joined with each other.
 2. The compressor according to claim 1, wherein the valve member of the discharge valve further comprises:. a board portion having a larger diameter than the discharge port, the board portion being capable of contacting a surface of a member for forming the discharge port in a predetermined area when the discharge port is closed; and a pillar-shaped protruding portion that extends from the board portion toward the discharge port, the protruding portion having a smaller diameter than the discharge port, the protruding portion and the board portion being integrally formed so as to be solid, thickness of the valve member being formed so as to be larger than that of the arm member.
 3. The compressor according to claim 2, wherein the board portion of the valve member has formed in a surface thereof which faces the discharge port forming member an annular groove concentric with the board portion.
 4. The compressor according to claim 1, wherein the valve member is cast in a resin material and the arm member is cast in metallic material which is different from the resin material, the valve member and the arm member being integrally joined with each other.
 5. The compressor according to claim 1, wherein a material of the arm member is a steel wire which has a predetermined rigidity.
 6. The compressor according to claim 1, further comprising a member that protrudes from a wall surface of the discharge chamber of the cylinder housing, a maximum lift amount of the discharge valve being regulated when a distal end of the protruding member contacts the valve member. 